As so often with your stories, I started reading this one and couldn't stop! I love that it can be read multiple ways: both as a non-magical AU in which Remus very probably is HIV positive, and as a take on canon in all its miserable glory.

I like the respect that you give to both characters here. Tonks is young and hopeful (possibly a little naive, but never pathetic), and Remus is...well, Remus is lovely - it's great to see the outsider viewpoint again, which we haven't really had since Harry in PoA.

The last line is gorgeous. For me, you've captured this wistful pairing perfectly here.